Calcium phosphate cements which are prepared by combining a dry component(s) and a liquid to form a flowable paste like material that is subsequently capable of setting into a solid calcium phosphate product hold great promise for use as structural materials in the orthopedic and dental fields. For example, it is desirable to be able to inject a flowable material into a cancellous bone void and have the material set into a solid calcium phosphate mineral product that is capable of withstanding physiological loads. Materials that set into solid calcium phosphate mineral products are of particular interest as such products can closely resemble the mineral phase of natural bone and are susceptible to remodeling, making such products extremely attractive for use in orthopedics and related fields.
Calcium phosphate cements that have been developed to date, while capable of setting in vivo into a product that resembles the mineral phase of natural bone and providing the benefits described above, have been less than ideal in terms of their preparation and methods of use. Specifically, cements that have been developed and marketed to date have required the user, such as the doctor, nurse or other health care practitioner, to manually combine the various components of the cement in a sterile field, load the resultant paste into a suitable delivery device such as a syringe, and then introduce the paste to a physiological site of interest.
Disadvantages associated with these present methods of preparing and using calcium phosphate cements include the requirement that the entire preparation process be carried out in a sterile field, the potential for inadequate or suboptimum mixing of the various components, and the overall number of different steps required and the concomitant time requirements placed on the health care practitioners.
Accordingly, there is great interest in the development of improved systems for the storage, preparation and delivery of a calcium phosphate cement to a physiological site of interest. Ideally such a system should provide for long term storage of the components in a convenient and easy to use format. Such a system should also provide for automatic and complete combination of the various cement components, preferably in a non-sterile field while maintaining the sterility of the cement being prepared. Finally, such a system should provide for easy and controllable delivery of the components to a site of interest without having to substantially expose the cement to the environment and/or manually pack the cement into the delivery means.